Grade-mounted light fixtures perform a variety of desirable functions, such as illuminating buildings, flag poles, trees, shrubs and sign boards. Such lighting fixtures are grade-mounted because the fixtures are installed in recesses in landscape adjacent to the structure to be illuminated such that the uppermost surface of the light fixture is substantially flush or coplanar with the landscape surface.
Light fixtures installed in recesses in the landscape require special consideration in design and construction. Depending on the type of lamp used in the fixture, a ballast or transformer may be required. If a ballast or transformer is required, adequate room must be provided in the fixture for such electrical devices.
A typical incandescent lamp, similar to a ordinary house bulb, operates without a ballast or transformer. Lamps classified as low voltage will operate only with a transformer. High intensity discharge lamps require a ballast to operate properly. A typical ballast includes a core and coil, a starter and a capacitor for proper functioning of the high intensity discharge lamp. Such ballast occupies a relatively large volume. Additionally, such ballast should operate at a temperature cooler than or below its thermal rating for UL certification and for a maximum longevity. For operation of these electrical devices at cooler temperatures, it is often necessary to isolate the electrical devices from the heat produced by the lamp.
Known fixtures combine optical and ballast housings. Such integrally combined housings are disadvantages. When the lamp does not require a transformer or ballast, the fixture uses extra material resulting in excess weight and volume, and is more expensive. The known fixture housings cannot be easily adapted for the requirements of the lamp.